I discovered Marvin, and it looks great, but I cannot understand what is the best way to keep in sync my books between my mac and my iphone. I would love to able to leave a bookmark on marvin, and find it on my mac.

As far as I know, the only app that shares a book mark across multiple platforms (iPad, Mac, and Android) is the Kindle app.

I don't think there's an actual Mac app, but Google Play Books do have a browser/cloud reader and it syncs with the various apps they have (iOS, Android, etc.). You can also upload your own ePub's to their cloud for reading with their system.

Thanks, but to clear up what I was looking for was a capability to sync the book wheter I had been reading it with the calibre ebook-viewer in my desktop or with Marvin on my iPhone or iPad. At this point I guess that isn't possible.